1. Field of the Invention
The present invention relates to a flare evaluation method, a flare compensation method, and a test photomask for an aligner used in a lithography process that is one of manufacturing processes of a semiconductor device.
2. Description of the Related Art
In recent years, a projecting aligner of a dioptric system or catadioptric system is used when forming patterns in a semiconductor element, in which light in an optical path different from the designed one is generated because of reflection and scattering on the surface and inside of a lens of an illumination optical system, a mask, a projection lens, and so on and unevenness in refractive index of lens materials and so on. This is a phenomenon called flare.
Lately, there has been a growing demand for microfabrication and high integration of a semiconductor device, and along with this, exposure light employed in the projecting aligner has been decreased in wavelength. Specifically, exposure light having a wavelength of 193 nm is employed. However, flare, which locally occurs depending on an exposure pattern due to a lens material associated with such a short wavelength, comes to be seen as a problem. This is so-called local flare that becomes a main cause of unintended change in the shape and the line width of a pattern to be transferred.
The above-described local flare needs to be quantified and removed in order to satisfactorily form each intended pattern in a semiconductor device. The local flare, however, is a problem that has recently been focused on as described above, and thus, in the present circumstances, no preferable technique has been supposed yet for intentionally solving the problem giving an attention to the local flare.